We propose to develop a new type of solid state photodetector to replace the photomultiplier tube in Anger-type scintillation cameras. The new detectors will be based on the silicon drift photodetector (SDP) structure. This technology is superior to other technologies that have been used to attempt to accomplish this goal in the past. Simulations and preliminary measured results with this new technology suggest that intrinsic spatial resolution of 1-2mm and energy resolution of 7-10% FWHM at 140keV are possible in a scintillation-camera based on the new technology. In Phase I we will explore the feasibility of achieving these goals. Simulation studies will be performed to investigate the effects of the various photodetector parameters on the achievable camera performance. Based on these studies we will fabricate the photodetectors and design, construct and evaluate small-area ( approximately 100 cm2) Anger cameras based on 0.5 - 1 cm2 photodetectors and scintillation crystals such as CsI(Tl) or NaI(Tl). In Phase II we will fabricate and demonstrate a complete anger camera prototype with a approximate 30cm diameter field of view constructed with the new photodetectors. PROPOSED COMMERCIAL APPLICATIONS: This technology has potential for replacement of photomultiplier tubes used in conjunction with scintillation crystals for gamma-ray spectroscopy, nuclear medical imaging, photon counting, etc. The overall market for the instrumentation in these areas is in the billions of dollars. The portion of this market addressed by this technology is in the hundreds of millions of dollars.